Ignition system



June 7, 1960 E. D. COOK 2,940,013

IGNITION SYSTEM Filed Dec. 27, 1957 2 SheetsSheet 1 F L2 1m 1" ml 5 5 1m. 1m 1m.

A l l Inventor: i Ellsworth D. COOK, E i by a .M N i- His Attorvfiey June 7, 1960 E. n. COOK 2,940,013

IGNITION SYSTEM Filed Dec. 27, I957 2 Sheets-Sheet 2 F I a b A "ll HI} ml 5 AIL Ii. ml 1 w 7 A 72 55 l l I l l l l I l 73 :l 7.; 75 l l J. a;

I of 7 Inventor.- E/lsworth D. Coo/T,

by Q1 QM H/lsAttorneg- States IGNITION SYSTEM Filed Dec. 27, 1957, Ser. No. 705,664

14 Claims. (Cl. 315-172) This invention relates to ignition systems for internal combustion engines and, more particularly, to an ignition system utilizing a saturable magnetic device.

One of the principal objects of this invention is to provide an ignition system which relieves breaker point loading. As is well understood by those skilled in the art, present-day ignition systems comprise, basically, a spark coil having a low voltage primary energized from a unidirectional source such as a car battery and a high voltage secondary connected to a distributor. High voltage ignition impulses for breaking down the spark gap in the engine spark plugs are produced by means of breaker points in the piimaryof the spark coil which are actuated by a cam operated contactor to interrupt the circuit periodically, with the rapid change in flux produced by the interruption of the primary current producing a lugn voltage impulse by induction in the secondary of the coil.

Upon analysis it becomes quite apparent that the breaker points are the weak link in the system and constitute the limiting factor in efficient operation. The breaker points in the ignition system must carry the entire primary current and carry them for firing of all of the cylinders in the engine, causing attrition and ultimate destruction of the breaker point surfaces. A consequence of this surface attrition, in addition to the necessity for periodic replacement, is a progressive deterioration of the ignition system and engine performance, since surface destruction decreases'the rapidity with which the primary circuit can be interrupted, preventing the formation of steep wave front pulses in the secondary coil and limiting the secondary voltage magnitude. the degenerated ignition impulses, proper ignition is hindered resulting in poor engine performance and increased gas consumption.

in addition to poor performance and excessive gas consumption, the system is extremely inefiicient since a major portion of the system power is dissipated across the breaker points rather than in the spark discharge. Because of this inherent inefficiency, large power sources are necessary in order to supply sufiicient power both for the spark discharge as well as that lost at the breaker points.

The present trend in modern engines towards increasing horsepower and compression ratios require higher power levels at the spark discharge gaps, consequently, accelerating attrition of the breaker points. Hence, the problem of breaker point attrition and poor engine performance becomes acute with spiralling compression ratios in modern engines.

It is another object of this invention, therefore, to provide an ignition system of greatly increased efiiciency by reducing losses at the breaker points.

A further object of this invention is to provide an ignition system of extremely high reliability.

Still another object of this invention is to provide an ignition system for internal combustion engines which uses an alternating current energy source.

Because of atent O oration control system indicated generally at 6 which is ZfiihfilB Patented June 7, 1960 trical power to the spark plugs.

A still further object of this invention is to provide an ignition system which is simple in construction, inexpensive to manufacture, and highly reliable in operation.

Other objects and advantages will become apparent as the description of the invention proceeds.

The above objects are achieved by utilizing a saturable magnetic device to release power periodically from an alternating current source to the spark plug circuit. The 'saturable magnetic device includes a unidirectional control winding energized in synchronism with the engine by means of a breaker point assembly to control the saturation of the magnetic device. Thus, the breaker points act as the synchronizing means to supply electrical power to the spark plugs by controlling the saturation of the magnetic device and do not carry the primary current. By thus reducing the load on the breaker points the attrition of the breaker point surfaces is reduced, increasboth as to its organization and method of operation together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 is a schematic diagram of an ignition system embodying the instant invention;

Figure 2 is a fragmentary showing of an alternative embodiment of the apparatus of Figure 1;

Figure 3 is an alternative construction of the ignition system illustrated in Figure 1;

Figure 4 is an idealized hysteresis loop useful in explaining the operation of the saturable magnetic device of Figures l3;

Figure 5 is an alternative embodiment of an ignition system utilizing a different type of saturable magnetic device; and

Figure 6 is an alternative embodiment of the ignition system of Figure 5.

Referring now to the drawings, Figure 1 illustrates an embodiment of the invention suitable for providing ignition impulses for a six cylinder internal combustion engine, although the invention is obviously useful with an engine of any number of cylinders. A source of alternating voltage, indicated generally at 1, which may be a static oscillator or a tachometer generator, provides an alternating voltage of a high frequency relative to the firing rate of the engine spark plugs. The alternating voltage source 1 is coupled to a low voltage primary Winding 2 mounted in flux exchange relationship with a core 3 of a saturable transformer 4. The transformer is characterized by normal transformer action between the winding 2 and a high voltagesecondary winding 5 when the core 3 is in its unsaturated condition, whereas ideally no transformer action occurs when the transformer is saturated. The core 3 is formed of so-called rectangular hysteresis loop material which, as is well known to those skilled in the art, has a sharp cut-off point between conditions of saturation and non-saturation so that the impedance of the inductive windings can change almost instantaneously from a high value to substantially zero, a hysteresis characteristic which is illustrated ideally in Fig. 4.

To control the saturable transformer 4 and produce the periodic steep wave front ignition impulses in the secondary high voltage winding 5, there is provided a satoperated in ,synchronism with the engine to control the saturation of the transformer. winding 7 mounted in flux exchange relationship with the core 3 controls themagnetizing force in the core and,

consequently, its saturation condition. The controliwinding 7 is operated in synchronism with the internal conibustion engine and produces acore magnetizing force which, when the unidirectional current flows therethrough,

maintains the core 3 in a saturated condition, precluding V the coupling of energy from the alternating voltage source 1 through the secondary winding 5 of the transformer. The winding 7 is connected in series with a unidirectional voltage source 10, such as a battery, through a current-limiting resistor 11, a lead 12, and a breaker point assembly 13. This assembly comprises a fixed breaker point 14'and a second movable breaker point mountedv on a breaker arm 15, which is operated in desired time relation with the engine operating by means of cam 16 and shaft 17 driven by the engine.

The breaker assembly 13 and particularly the movable breaker arm 15 provides the means by which the control winding current is periodically interrupted in synchronism with the engine to remove the saturating magnetizing nating voltage source 13 into the secondary 5 of the transformer 4. Hence, the six lobed cam 16 mounted on a cam shaft 17, which may be the usual timing shaft of the engine 18, is arranged to actuate the movable breaker arm 15 periodically to interrupt the circuit between the source of unidirectional voltage and the winding 7. Upon the periodic actuation of the breaker point assembly 13' the saturable transformer 4 is permitted to couple energy to the secondary high tension winding 5, one end of which is grounded and the other connected through a distributor 19, which is also driven by the camshaft 17, to distribute the voltages through distributor points 20 to the appropriate spark plug 21 of the internal combustion engine.

To this end a control force from the core.3, releasing power from the alter-v In operation, the high frequency alternating output of the source 1, indicated by the wave form a in Figure 1',

is not coupled to the distributor 19 as long as the breaker point assembly 13 is in its normally closedposition since 7 the ampere-turns of winding 7 produce a magnetizing force H whichsaturates the core 3 and, as is illustrated in Figure 4, maintains the core in negative saturation. Since, the necessary ampere turns for this function can be obtained by using many turns of wire in winding 7, the current in winding 7 is low and hence little power is used in this circuit. Thus, breaker point destruction is reduced. Upon actuation of the breaker point assembly,13 by cam 16 to open contacts 14 and 15, the magne tizing force H produced by winding '7 is removed from the core and the core is driven towards apoint --l3 on line ND of Figure 4. [Due to the rectangular hysteresis loop characteristics of the core material, the next alternation of the voltage from source 1 permits an almost instantaneous unsaturation of the core suddenly releasing power from the source 1 into the secondary winding 5 Upon the closing of the breaker points 14 and 15 the v circuit of winding 7 isonce again completed, applying magnetizing force H7 to the core 3, driving it to saturation and preventing further power from being transmitted to the'secondary and producing the steep back portion of the pulse waveform illustrated at b. In this fashion each camshaft initiated interruption of the breaker point assembly 13 drives .the core of the saturable transtems. Hence, the breaker points do. not handle as much power as formerly and are not subject to surface attrition.

In the ignition system of Figure 1, but a single direct current control winding 7 is utilized to control the condition of the core member 3. That is, since the frequency of the alternating voltage from the source 1 is high compared to the rate at which the breaker point assembly is operated, the high frequency voltage alternations bring the core 3' of the transformer 4 to its unsaturated condition very rapidly. In some cases, however, it may be desirable, even with an alternating voltage source of high frequency relative to the breaker assembly operating rate, to utilize a bias winding which, in the absence of the magnetizing force H brings the state of the core to a point (illustrated at d in Figure 4) just short of the abrupt change in flux. Thus, a small voltage from source 1 produces a large and very rapid change of core flux conditions.

Figure 2 is a fragmentary showing of the saturation control circuit 6 of Figure 1 with the provision of such a bias winding. A pair of windings 7 and 8 are mounted on a core 3 to control the magnetizing force. The winding 8 is a bias winding which sets an ambient magnetizing force in the core with no current flow through control winding 7. The'winding 8 is connnected through a current-limiting resistance 9 across the unidirectional source 10 and is Wound in such a manner to produce a core magnetizing force H; which opposes that of winding 7 (H and drives the core 3 to the point d on the hysteresis loop whenever the breaker point assembly 13 interruptsthe current flow through winding 7.

The ignition circuit illustrated in Figure 3 employs an alternating voltage source 31 driven by the internal combustion engine'to' replace the voltage source 1 in Figures .1 and 2. The alternating voltage source 31 of Figure 2 may be a tachometer or the like which is driven directly by the engine through the timing or cam shaft 17 whereby the frequency of the voltage is'proportional to engine speed. That is, the output frequency from the tachometer generator 31 may be nearer to the interruption rate of .the breaker assembly whereas in the circuit of Figures 1 and 2 the frequency is high compared to the interruption rate of the breakerpoint assembly. In all other respects the circuit of Figure 3 is identical to that of Figures 1 and 2 with corresponding elements designated by like reference numerals. The output from the tachometer generator 31 is connected to the primary low voltage winding .2 of saturable transformer 4 and is mounted in flux exchange relationship with a core 3 formed of a rectangular hysteresis material. A secondary high voltage winding 5 is also mounted on the core element 3 and couples steep wave front ignition impulses to the engine spark plugs. In a fashion similar to that described with reference to Figure 1, a saturation circuit-6 is provided for controlling thesaturation of the transformer thereby producing the periodic ignition impulses. The saturation circuit comprises a bias Winding 8 and a control winding 7 mounted on the core element 3 and being wound in such a sense that the magnetomotive forces produced thereby are opposing with that of the control winding 7 being much larger than and overriding the effects of the bias winding 8. 7 The bias winding 8 is connnected through a currentlimiting resistor 9 across a source of unidirectional voltage 10, such as a car battery or the like, whereas the control winding is connected through a current-limiting resistance 11, lead 12 and a breaker point assembly 13 to the same unidirectional voltage source. The breaker assembly 13 comprises a fixed breaker point 14 connected to the lead 12 and a second breaker point mounted on a movable breaker arm 15 actuated by a cam 16 driven by and mounted on the cam shaft 17 of the engine 18.

'In a manner similar to that described above, the circuit 7 grounded at one end and connected to a distributor 19 at its other to distribute voltages through the distributor points 26 to the appropriate spark plug 21.

It is to be understood, of course, that the tachometer generator 31 is constructed, as is well understood by those skilled in the art, to have a multiplicity of pole pairs so that the output voltage goes through several cycles for each rotation of the cam shaft 17. In addition, the generator is synchronized so as to be properly phased with the cam shaft whereby the polarity of the alternating voltage is of the proper polarity to produce almost instantaneous unsaturation of the core when breaker assembly 13 opens the circuit of control winding circuit 7 and allows the magnetizing force H; of winding 8 to act upon the core.

Where the alternating voltage is of a frequency which is not high relative to the breaker assembly operational rate, so that the period of the alternating voltage is a significant portion of the breaker assembly operation, the importance of the bias winding is increased. That is, were the bias winding not present, the removal of the control winding magnetizing force H still leaves a residual flux density, indicated in Figure 4 as B in the core 3 and, hence, a finite period of time is necessary to bring it to the unsaturated condition. This finite time necessary to produce the coercive force necessary to overcome the residual flux density may constitute a significant portion of the period of the alternating voltage cycle and constitutes spark retard or advance conditions larger than desirable. The presence of the bias winding, however, provides the coercive force to counteract the residual flux in the core 3, permitting the core 3 to pass to its unsaturated condition almost instantaneously eliminating the problem of spark advance and retard.

The ignition system described with reference to Figures l-3 utilizes a saturable magnetic device of the saturable transformer type wherein a unidirectional control winding controls the saturation of a core element to release energy periodically into the secondary circuit. In alternative embodiments, illustrated in Figures 5 and 6, the saturable magnetic device of the ignition system is a magnetic amplifier and load circuit connected in series across a source of alternating voltage with the load circuit coupled to the spark plugs. The magnetic amplifier is periodically saturated by means of a breaker point control winding permitting the load circuit to couple steep fronted ignition impulses to the spark plugs.

Referring now to Figure 5, a high frequency alternating voltage source, illustrated generally at 50, is connected in series with a magnetic amplifier assembly 51 and the primary winding 52 of a transformer 54 having a secondary winding 53 coupled thereto and to the spark plugs. The

magnetic amplifier 51 comprises a pair of reactance windings 55 and 56 wound preferably on the legs of two,

preferably separate, magnetic core members (not shown) characterized by a rectangular hysteresis loop, one end of each winding being connected .to the source of alternating voltage 50 and the remaining end to a pair of rectifier elements 57 and 58 so poled as to permit current flow through the different windings during opposite half-cycles of the voltage from the source 50.

The operation of magnetic amplifier 51 is controlled by a bias winding 59 and a control winding 60, the two winddings being wound and arranged in such a sense that their 'm-agnetomotive forces and hence the fluxes produced thereby oppose. The bias winding 59, in a manner similar to thatdescribed with reference to Figures 1 and 2, is connected through a current-limiting resistor 61 across the terminals of a unidirectional voltage source 62 such as a car battery or'the like. Control winding 55, on the other hand, is connected through a current-limiting resistance 63, lead 64, and fixed breaker point 65, and a movable breaker arm 66 of breaker assembly 67 across the same unidirectional voltage source 62. The breaker point assembly 67 connected in the control winding circuit is actuated by means of a six lobed cam 68 mounted on and driven by a cam shaft 69 from a six cylinder internal combustion engine 70. The breaker point assembly 67 is so constructed that the breaker points 65 and 66 are normally maintained in their open condition and are periodically closed by the action of the cam 66 to close the circuit of the control winding 60 permitting current .to flow therethrough from the battery 62.

The periodic closing of the breaker points by means of the six lobed cam 68 closes the circuit of the control winding applying a magnetizing force to the core members of the saturable reactors 55 and 56 sufiicient to saturate the magnetic amplifier whereby its impedance drops almost to zero and substantially the entire alternating voltage from the source 50 appears across the primary winding 52 and is coupled to the secondary winding 53 producing steep fronted wave ignition impulses. The secondary winding 53 is grounded at one end and the other is connected through distributor 71, which is driven by the cam shaft 69, to distribute the voltage impulses through the distrbiutor points 72 to the spark plugs 73.

The operation of the ignition system of Figure. 5 may be explained as follows: the operating characteristics of a magnetic amplifier, such as is illustrated at 51, is such that in its unsaturated condition it has a high impedance and most of the voltage from the alternating source 50 appears thereacross and as a consequence substantially no power is coupled into the high tension secondary circuit through the transformer. In its saturated condition, however, the amplifier has an impedance which is very close to zero and as a consequence most of the voltage from the alternating current source 50 appears across the primary 52 and is coupled through the medium of the high tension secondary 53 to the spark plugs of the engine.

Thus, the manipulation of the control Winding 60 through the instrumentality of the breaker point assembly 67 causes the magnetic amplifier 51 to saturate periodically releasing energy to the firing circuits and their associated spark plugs. Thus, there appear in the secondary high tension winding 53 periodic steep fronted ignition impulses iliustrated by the waveform b. Once again, the breaker point assembly illustrated in this ignition system carries only a very small current load since the breaker points are utilized not to carry the main current but to synchronize the operation of the ignition system to provide electrical power to the spark plugs at the proper instant.

The ignition system illustrated in Figure 6 differs from that in Figure 5 in that it employs an alternating voltage source driven directly from the engine and producing an output voltage having a frequency proportional to the engines speed. All other elements in Figure 6 which correspond to elements shown in Figure 5 are designated by like reference numerals. The operation of the system comprises magnetic amplifier 51 connected in series with the primary 52 of the transformer across an alternating voltage tachometer generator 81. The amplifier 51 again on a pair of separate, core members characterized by rectangular'hys'teresis loop, with one end ofeach winding being connected to a tachometer generator 81'drivenby 'the engine and the remaining endto apair of rectifiers 57 and 58 so .poled as to permit current flow to the respective reactance; windings during alternating half-cycles of the voltage'provided by the tachometer 81; control winding 6! .connected to a. current-limiting resistor-63 and, a

pair of breaker points 65 and 66 of abreaker'point'asF sembly 67 is connected across a' unidirectional source of voltage 62 such as a'battery or the like; -A bias winding 59 is connected through a current-limiting resistance 61 to one terminal of the unidirectional'source 62, the other end of the winding being connected to the remaining terminal.

.The windings "59: and60 provide magnetizing forces which control the condition of the cores, of the respective reactance windings 55. and 56"with'the control winding 60 causing periodic saturation of .the amplifier device. The breaker point assembly 67 is actuated'by means of a :six lobed cam 68 mounted on and. driven by a camshaft 69 which is driven directly from'anengine 70. The

breaker points and the breaker point assembly are so constructed' that the breaker points 65 .and 66 are normally open and the cam 66 periodically closes the breakers energizing the control winding 60 driving the magnetic amplifier 51 to saturation. As described previously, the saturation of the magnetic amplifier 51 reduces its reactance substantially to zero thus applying substantially all of the voltage from the voltage generating tachometer 81' across the primary 52 of the transformer and coupling energy to the secondary 53. The secondary 53*has one end thereof connected to ground and the remaining one to distributor .71 which is driven by the cam shaft 69 to distribute the voltage ignition impulses through the' distributor points 7210 the respective spark plugs 73. i

The operation of the ignition system of Figure 6 is identical to that of Figure with the magnetic amplifier having a high impedance during its unsaturated condition with substantially all of thealternating voltage appearing there across preventing the transmittal of energy through the transformer to the spark plugs. Upon the periodic saturation of the magnetic amplifier its impedance drops substantially to zero and most of the applied voltage from the tachometer appears across the primary 52 of the transformer and is thence coupled through the secondary 53 and the distributor 71 to the respective spark plugs 73. In this fashion periodic steep wave front ignition impulses are produced to be applied to the spark plugs, which impulses are produced without utilizing breaker points to interrupt the entire primary current. That is, once more'the breaker point assembly is positioned in the control winding circuit and, hence, interrupts a current which is very small in comparison to those which must be interrupted in presently available ignition systems.

It will be appreciated from the description preceding that an' ignition system has been provided which is effective, reliable, etficient, and inexpensive. It can also 'be seen that the mechanical interrupting means for synchronizing the generation of the impulses are not subject to the high attrition rate presently to be found in ignition systems. Hence, an efiective and valuable new ignition system has been invented anddisclosed by applicant.

While particular embodiments of this invention have been shown it will, of course, be understood that it is not limited thereto since many modifications both in the circuit arrangement and in the instrumentalities employed may be made. It is contemplated by the appended claims to cover any such modifications as fall Within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1., The combination, in a system for supplying ignition sparking voltage to the fuel ignition spark gaps of an internal combustion engine, of a saturable magnetic decomprises a' pair of saturable reactances 55 and 56 wound 'vice including a saturable core member, said saturable magnetic device having an input and an output, and means to supply alternating voltage to said input for'reproduction at said output in amplified'form for use as said spark- 5 ing voltage, and low power circuit means alternatelyto '10 2; In an ignition system, the combination comprising .a source of alternatingvoltage, a saturable magnetic de- -vice h aving a'saturable core member, said saturable magnetic device being coupled to said voltage and including alowpower'saturation control circuit, and mechanical ,timing means connected in said saturation circuit to produce a smallenergy change in said circuit and thereby control saturation of said core and said magnetic device to produce alargeignition sparking voltage.

3. In an-internal combustion engine ignition system,

.the combination comprising a source of alternating voltage, a saturable-magnetic device coupled to said voltage source,-.said saturable magnetic device including a saturable core member, a low power control circuit having a unidirectionalvoltage control winding mounted in flux exchange relationship withsaid core, a source of unidirectional voltage connected in said control circuit, mechanical timing means connected in said circuit and operated in synchronism with said internal combustion engine to produce a small energy change in said circuit and thereby control saturation of said core and said magnetic deviceso that a large ignition sparking voltage is produced with each operationtof the timing means.

' 4. In an internal combustion engine ignition system, thecombination comprising a saturable magnetic device 'having a .saturable core member and a low power control circuit, said low power control circuit including a saturation control winding mounted in flux exchange relationship with said core, a voltage source connected in 'said control circuit, mechanical interrupting means includingbreaker points actuated in synchronism with said internal combustion engine connected-to said 'winding to cause control current to flow and produce a small energy change. in said circuit and thereby control saturation of said core and said magnetic device, and asource of alternating voltage coupled to said saturable magnetic device, said. alternating'voltage having a frequency which is high relative to the interrupting rate of said mechanical means. 5. In an internal combustion engine ignition system, 'the combination comprising saturable magnetic device having a saturablecore and a low power control circuit, said control circuit including a saturation control winding mounted in flux exchange relationship with said core, a unidirectional voltage source connected in said control circuit'to provide a flow of control current in saidcircuit, mechanical interrupting means including breaker points 7 actuated in synchronism with said internal combustion engine speed connected to said control winding to cause said control current to flow and produce a small energy change in said circuit and thereby control saturation of said core and said magnetic device, and an alternating ,voltage generator means coupled vto said saturable magnetic device. driven by said engine whereby the frequency of the alternating voltage produced thereby is propor-.

7 .chronism with said engine toproduce a small energy change in said circuit and thereby control saturation of said core and said transformer whereby periodic steep wave front ignition impulses are produced.

7. In an ignition system for firing spark plugs in an internal combustion system, the combination comprising an alternating voltage generating means adapted to be driven by said engine, a saturable transformer comprising low voltage primary and high voltage secondary windings and a low power control circuit including a unidirectional current control winding mounted in flux exchange relationship with a saturable magnetic core having substantially rectangular hysteresis loop characteristics, said primary winding being connected to said generating means and said secondary Winding adapted to supply ignition impulses to engine spark plugs, breaker points connected in series with said control winding actuated in synchronism with said engine to produce a small energy change in said circuit and thereby control saturation of said core so that steep wave front ignition pulses are produced in the high voltage secondary winding during the non-saturated periods.

8. In an internal combustion engine spark plug ignition system, the combination comprising a source of alternating voltage, a magnetic amplifier connected in series with a load circuit across said voltage source, said magnetic amplifier having a low power control circuit means including a control winding, said load circuit being adapted to supply ignition pulses to said engine during the saturated periods of said amplifier, a source of unidirectional voltage connected in said control circuit, and breaker points connected in series with said control winding and said unidirectional source and actuated in synchronism with said engine to produce a small energy change in said circuit and thereby control saturation of said magnetic amplifier means so that steep wave front ignition pulses are produced across said load circuit during the saturated periods of said amplifier.

9. In an internal combustion engine spark plug ignition system, the combination comprising an alternating voltage generating means adapted to be driven by said engine, a magnetic amplifier connected in series with a load circuit across said voltage source, said load circuit being adapted to supply ignition pulses to said engine during the saturated periods of said amplifier, said magnetic amplifier including a low power control circuit having a control winding, a source of unidirectional voltage connected in series with said control winding, and breaker points connected in series with said control winding and said unidirectional source and actuated in synchronism with said engine to produce a small energy change in said control circuit and thereby control saturation of said magnetic amplifier means so that steep Wave front ignition pulses are produced across said load circuit during the saturated periods of said amplifier.

10. In a system for supplying ignition impulses for the fuel igniting sparking electrode of an internal combustion engine, a source of electrical power to supply energization to said electrode, coupling means between said source and said electrode, said coupling means including a saturable impedance means, and means to saturate said impedance in timed relation with said engine to produce short intense pulses at the output of said coupling means.

11. In a system for supplying ignition impulses for the fuel igniting sparking electrodes of an internal combustion engine, a source of electrical power to supply energization to said electrodes, coupling means between said source and said electrodes, said coupling means including a saturable impedance, means to saturate said impedance in timed relationship with said engine to produce intense ignition impulses at the output of said coupling means, and means synchronous with said engine to distribute said intense impulses to said electrodes in desired timed relation with said engine.

12. In an ignition system for supplying ignition impulses to the fuel igniting electrodes of an internal combustion engine, the combination of a source of alternating current, a magnetic coupling means between said source and said electrodes, said magnetic coupling means having a saturable core and an output winding thereon, means to produce saturation of said core to form intense ignition impulses at said output winding in desired timed relation to the operation of said engine, and means synchronous with the engine to distribute said pulses to said electrodes.

13. in an ignition system for supplying ignition energy to fuel igniting sparking electrodes, the combination comprising a saturable transformer means having a saturable core member and primary and secondary windings mounted in flux exchange relationship with said core member, a low power control circuit including a saturation control winding mounted in flux exchange relationship with said core member, a direct current energy source connected in said control circuit to provide a control current for saturating said core and said transformer, me chanical interrupting means including breaker points actuated in synchronism with said internal combustion engine speed connected to said winding to cause said control current to flow and produce a small energy change in said circuit and thereby control saturation of said core and said transformer, and a source of alternating voltage coupled to the primary winding of said transformer, said voltage having a frequency which is high relative to the interrupting rate of said mechanical interrupting means.

14. In an ignition system for supplying ignition energy to the fuel igniting sparking electrodes of an internal combustion engine, the combination comprising a magnetic amplifier connected in series with a load circuit, said magnetic amplifier having a low power control circuit means including a control winding, a source of unidirectional voltage connected in said control circuit to provide a control current for saturating said amplifier, and breaker points connected in series with said control winding and unidirectional source to be actuated in synchrom'sm with said engine to cause said control current to flow and produce a small energy change in said circuit and thereby control saturation of said magnetic amplifier, a source of alternating voltage coupled to said amplifier and load having a frequency which is high relative to the interrupting rate of said mechanical means, whereby ignition impulses comprising bursts of said alternating voltage are produced across said load circuit during said saturated periods of said amplifier.

References Cited in the file of this patent UNITED STATES PATENTS 1,225,536 Varley May 8, 1917 1,534,384 Hawkins Apr. 21, 1925 2,306,578 Wetzel Dec. 29, 1942 2,377,793 Linlor June 5, 1945 2,466,028 Klemperer Apr. 5, 1949 2,566,260 Thomson Aug. 28, 1951 2,757,297 Evans et a1. July 31, 1956 2,768,312 Goodale et a1 Oct. 23, 1956 

